It's pretty likely to hear me say (often) "Get it written, THEN get it right."
I say this for the obvious reason. Many people get hung up around the thought that they can't get it "right" so they obsess in the outlining phase, or they write and rewrite the first chapter ad infinitum. For these folks, my advice is right on the money. Write it first...then get it right.
There is a second part though...when I say get it right, I mean really get it right.
If you want to attract a publisher, sending them a crap manuscript is not "getting it right". After you get it written, you need to spend a while getting it right. This, to me, is the hardest part because you want to be doing something else, but you have to force yourself to focus on getting your work right. This means editting, polishing, rewriting, etc.
You need to get all of this done before sending it to an editor. If you want to stand out, then a great story is part of it. Good characters is part of it. Sending them a work that is already substantially "right" will definitely help get some attention.
If you plan on foregoing a traditional publisher and do it yourself...then getting it right is even MORE crucial! You'll have a huge stigma to overcome. That stigma is out there for a reason. Lots of do-it-yourself books don't have the quality of a traditionally published one. They can. They should. People just haven't taken the time to do the second part. I have bought several self published works with a great storyline, awesome characters and even a really nice looking book with an eye-catching cover, only to have my heart broken by poor editting, common errors and stilted dialogue.
So, now that you've got it written, now you really have to get to work.